Carlos Eduardo Navarro Risco - Academia.edu (original) (raw)
Papers by Carlos Eduardo Navarro Risco
Journal of Dairy Science, 2005
Trends in reproductive performance from 1976 to 2002 were studied for dairy farms located in Flor... more Trends in reproductive performance from 1976 to 2002 were studied for dairy farms located in Florida and Georgia using 2,897,517 Dairy Herd Improvement Association lactation records of Holstein cows. One-half of the 1552 herds in the final edited records had measures for at least 8 yr. Measures of reproductive performance changed significantly over time. Days to first service increased from a low of 84 d in 1983 to 104 d in 2001. Cows that calved during spring had 9.2 (1983) to 33.2 (1999) more days to first service than cows that calved during fall. Annual pregnancy rates (PR) for 71 to 364 d since last calving (DSC; PR 71-364) decreased from 21.6% in 1977 to 1979, to 12% in 2000 to 2002. The greatest PR 71-364 was observed during winter and the lowest during summer (15.8 vs. 5.6% in 2002, respectively). The absolute difference between PR 71-364 during winter and summer remained similar over time at 11 percentage units. Pregnancy rates in the early stages since calving (71 to 133 d) showed greater decreases over time than PR in the later stages since calving. From 1998 to 2002, PR in the later stages since calving (134 to 364 d) was on average 11.5%. Pregnancy rate from 71 to 133 DSC remained greater (13.4%). In the winter, the decrease in PR 71-364 was primarily due to a large decrease in PR 71-91. Average days to conception
Journal of Dairy Science, 2004
A longitudinal study was conducted to examine the relationship between lameness and delayed ovari... more A longitudinal study was conducted to examine the relationship between lameness and delayed ovarian cyclicity during the first 60 d postpartum and days to first luteal activity during the first 300 d postpartum in Holstein cows. Two hundred thirty-eight cows from a 600-cow dairy that calved during a 12-mo period were used. Cows were classified into 1 of 6 categories of lameness during the first 35 d postpartum using a locomotion scoring system. Cows were blood-sampled weekly for detection of plasma progesterone concentrations during the first 300 d postpartum. Cows with delayed resumption of ovarian cyclicity were defined as those with progesterone concentrations consistently <1 ng/mL during the first 60 d postpartum. The null hypothesis that risk of delayed cyclicity is the same in cows classified as nonlame, moderately lame, or lame (after adjusting for potential modifying or confounding effects of loss of body condition and other variables related with delayed cyclicity) was tested using logistic regression. Analysis of results of the study reported here support the hypothesis that lameness is associated with delayed ovarian activity in Holstein cows during the early postpartum period. Cows classified as lame had 3.5 times greater odds of delayed cyclicity, compared with cows classified as nonlame. Attributable proportion analysis indicated that delayed ovarian cyclicity in lame cows would be reduced by 71%, if lameness had been prevented.
Revista De La Facultad De Medicina Veterinaria Y De Zootecnia, May 3, 2010
From an animal health-well being, welfare, and performance perspective, the postpartum period is ... more From an animal health-well being, welfare, and performance perspective, the postpartum period is comprised of an early window where acute health and cow survival is an issue with the development of septic metritis. subsequently, sustained presence of endometritis is likely to be contributing to sub-fertility in lactating dairy cows with an overall herd pregnancy rate of approximately 16%. The challenge is to integrate on commercial dairies preventive medicine programs with reproductive management to improve herd fertility. Cows affected by periparturient disorders such as hypocalcemia, dystocia, and retained fetal membranes are more likely to contract uterine infections than cows that calve normally are. Thus, appropriate management of the transition period is critical in the prevention of uterine infections at the herd level. in addition, a postpartum program to monitor health to provide treatment to cows in the early stages of disease should be implemented.
Revista De La Facultad De Medicina Veterinaria Y De Zootecnia, May 3, 2010
Los días abiertos en el hato lechero dependen de muchos factores, dentro de los cuales se debe co... more Los días abiertos en el hato lechero dependen de muchos factores, dentro de los cuales se debe considerar, la preparación de la vaca preparto incluyendo el manejo dietario pre y postparto. Factores como la hipocalcemia y la condición corporal son determinantes en la presentación de patologías puerperales y en el inicio de la ciclicidad. adicional a este manejo, se debe considerar la utilización de protocolos de inseminación a tiempo fijo que incrementa el número de animales servidos cerca del tiempo voluntario de espera y genera un incremento en las tasas de preñez. La presente revisión discutirá temas relacionados con la condición corporal y la presentación de hipocalcemia puerperal que afectan la fertilidad posparto de la vaca, así como alternativas para mejorar las tasa de preñez y reducir los días abiertos.
The Canadian veterinary journal. La revue vétérinaire canadienne, 2007
Twenty-two cases of indigestion occurred in a 650-cow herd. Five cows had severe sand abomasal im... more Twenty-two cases of indigestion occurred in a 650-cow herd. Five cows had severe sand abomasal impaction, diagnosed by laparotomy. The pH of prepartum cows' urine was < 6.0 and of sand 8.0. Feed showed a dietary cation-anion difference < or = -110 mEq/kg. After feeding management corrections, no more cases were diagnosed.
Journal of Dairy Science, 2002
The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterifie... more The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and glucose in transition cows fed anionic salts prepartum and provided with calcium and energy supplements at calving. The study was conducted on a Florida Holstein dairy farm from November to December 1997. Treatments consisted of no treatment (n = 30); 60 g of Ca as calcium chloride, orally (n = 30); 110 g of Ca as calcium propionate 510 g plus 400 g of propylene glycol, orally (n = 30); two doses of 60 g of Ca as calcium chloride, one at calving and the second 24 h later, orally (n = 30); and 10 g of Ca as borogluconate, intravenously (n = 30). Treatments were administered within 12 h after parturition. Blood samples were collected at d 1 (parturition), 2, 3, 6, 9, and 12 after calving. Plasma total Ca, P, Mg, NEFA, BHBA, and glucose were measured. There were no differences in the concentrations of the blood metabolites among treatments.
Theriogenology, 2003
The objective of this study was to determine the effect of a calcium-energy supplement at calving... more The objective of this study was to determine the effect of a calcium-energy supplement at calving on the incidence of calving-related disorders (CRD), fertility, BCS and milk yield in cows fed anionic diets and to establish any associations among outcome variables. In Florida, from October to December 1997, 479 cows were assigned to three groups and treated at calving as follows: Group 1: 160 nontreated cows; Group 2: 158 cows, treated orally with 60 g Ca as CaCl 2 ; Group 3: 161 cows, treated orally with 110 g Ca as calcium propionate (510 g) plus propylene glycol (400 g). No treatment effect was detected for any of the outcome variables. An association was found between dystocia and age and retained fetal membranes (RFM). Age and RFM were associated with metritis. RFM and displacement of the abomasum were associated with ketosis. Ketosis and age were related to displacement of the abomasum. Parity, BCS, ovarian cysts, RFM and metritis were associated with fertility.
Theriogenology, 2006
The objective of this study was to evaluate the association between the level of milk production ... more The objective of this study was to evaluate the association between the level of milk production on the day of diagnosis of ovarian cysts and treatment response using the Ovsynch protocol. On the day of cyst diagnosis (Day 0), 260 lactating dairy cows with ovarian cysts were treated with gonadotropin-releasing hormone (GnRH), PGF2a on Day 7, GnRH on Day 9, and timed inseminated 16-20 h later (Ovsynch protocol). Pregnancy was determined (by transrectal palpation) between 42 and 49 days after insemination. On Day 0, data for milk production (kg/day), parity, days in milk (DIM), and body condition score (BCS) were recorded. Using the median value for milk production on the day of diagnosis, cows were classified as high producers (>28.5 kg) and low producers (28.5 kg). Cows were classified as primiparous (first lactation) or multiparous (second or more lactations). Data for conception rate (CR) were analyzed using logistic regression accounting for milk production on the day of diagnosis, parity, DIM, and BCS. The CR for low and high producers was 6 and 16%, respectively. There was no association between DIM and BCS with the other variables (P ! 0.05). Primiparous cows were more likely (adjusted odds ratio: AOR = 3.63; 95% CI: 95% confidence intervals = 1.28-10.30; P 0.01) to become pregnant than multiparous cows, and low producers were less likely (AOR = 0.31; 95% CI = 0.11-0.85; P 0.02) to become pregnant than high producers. It was concluded that cows with high milk production on the day of cyst diagnosis were more likely to become pregnant following treatment than cows with low milk production. It appears paradoxical that high milk production predisposes to the occurrence of ovarian cysts, but that high-producing cows respond better to treatment compared to low-producing cows. It is hypothesized that the level of milk production on the day of cyst diagnosis could be an additional potential predictor of success to treatment of lactating cows with ovarian cysts using the Ovsynch protocol.
Risco/Dairy Production Medicine, 2011
ABSTRACT
Hopper/Bovine Reproduction, 2014
Dairy Production Medicine, 2011
Risco/Dairy Production Medicine, 2011
... with various periparturient disorders such as uterine prolapse (Risco et al., 1984 ), retaine... more ... with various periparturient disorders such as uterine prolapse (Risco et al., 1984 ), retained fetal membranes (Risco et al., 1994 ; Mel é ndez et ... Cows with an abnormally enlarged uterus and a puru-lent uterine discharge without systemic signs of illness are classified as grade 1 ...
Veterinary Clinics of North America: Food Animal Practice, 2005
Veterinary Clinics of North America: Food Animal Practice, 2005
Vaccine, 2009
Mycoplasma bovis is an important cause of pneumonia, otitis media and arthritis in young dairy ca... more Mycoplasma bovis is an important cause of pneumonia, otitis media and arthritis in young dairy calves, and there is a critical need for improved preventative strategies for this pathogen. We conducted a randomized, placebo-controlled, double-blinded field trial to determine the efficacy of a commercial M. bovis vaccine for the prevention of M. bovis-associated disease in calves. Calves (n = 373) on 3 Florida dairies with a history of M. bovis infection received an M. bovis bacterin or a placebo, administered subcutaneously at 3, 14 and 35 days of age. One of the herds did not experience M. bovis-associated disease; for calves in the remaining 2 herds, the incidence risk for respiratory disease, otitis media and arthritis from 3 to 90 days of age was 0.64, 0.28 and 0.02, respectively. Vaccination had no effect on the age at first treatment for M. bovis-associated disease, incidence of respiratory disease, mortality, weight gain, or nasal colonization with M. bovis in the first 90 days of life. In one herd, vaccination was associated with an increased risk of otitis media. There was no association between M. bovis-specific serum antibody titers and morbidity in vaccinated calves. Under the field conditions in this study, this vaccine was not efficacious for the prevention of M. bovis-associated disease in young dairy calves.
Theriogenology, 2006
The objective of this study was to determine the effect of a monensin controlled-release capsule ... more The objective of this study was to determine the effect of a monensin controlled-release capsule on the incidence of retained fetal membranes (RFM), milk yield and conception rate at first service (CRFS). The study was conducted during May to August 2004 in a large dairy herd in Chihuahua, Mexico. Cows (n = 2025) from 20 to 30 d before expected parturition were randomly assigned to either a treatment or a control group. The treated group (n = 1010) received orally a capsule of monensin that released 335 mg/d for 95 d. Control cows (no capsule, n = 1015) were randomly assigned and matched by parity. Outcome variables were the incidence of RFM, first three test day milk and CRFS. Monensin decreased the incidence of RFM by 3.9% only in multiparous cows. Therefore, multiparous cows treated with monensin were 0.78 times (95% C.I. = 0.71-0.86) as likely as control multiparous cows to develop RFM. Overall, milk yield was negatively affected by the RFM condition, but it was improved by monensin only in multiparous cows with RFM at test day 1. Conception rate at first service was depressed by 10.6% in multiparous cows with RFM. However, in RFM cows treated with monensin, CRFS improved to the level of treated cows without RFM.
Research in Veterinary Science, 2007
The objective of this study was to determine the effect of a monensin controlled-release capsule ... more The objective of this study was to determine the effect of a monensin controlled-release capsule administered intraruminally at drying-off on body condition score (BCS) at calving, milk yield, fertility and concentration of energy-related blood metabolites in Holstein cows dried-off with low BCS (< or = 3.0, scale 1 to 5 with a 0.25 point of increment). Between July and August, 2001, 220 cows from parity 2 or more and dried-off 50-70 days before expected parturition, with a BCS < or = 3.0 were randomly assigned to either a treatment group (n=110; oral capsule of monensin releasing 335 mg/day for 95 days) or a control group (no capsule, n=110). At assignment, on day 21 before expected parturition, at calving, and at 7, 14, and 21 days in milk a blood sample was obtained from a random sub sample of 10 cows per group. Effects of monensin on serum NEFA, BHBA and glucose were measured. Milk yield, milk fat and protein content (%) at DHIA test days during the entire lactation, 305 ME milk production and reproductive responses were compared. Monensin significantly improved BCS at calving, increased milk yield at test days 4 and 8, decreased the percentage of milk protein, did not change the percentage of milk fat, and decreased NEFA and BHBA during the post-partum period.
Journal of the American Veterinary Medical Association, 2005
Objective—To compare calving-to-conception intervals among cows classified as nonlame, moderately... more Objective—To compare calving-to-conception intervals among cows classified as nonlame, moderately lame, or lame during the prebreeding postpartum period and to examine the relationship between severity of lameness and time to conception in cows that were classified as lame. Design—Longitudinal study. Animals—499 Holstein cows. Procedure—Cows in the prebreeding postpartum period were classified as nonlame, moderately lame, or lame by use of a 6-point locomotion scoring system. Time to conception (days) was compared among cows. A low, medium, or high cumulative locomotion score was assigned to lame cows, and time to conception among those cows was compared. Cows classified as lame were examined on a tilt table for diagnosis and treatment of lameness. Results—154 (31%), 214 (43%), and 131 (26%) cows were classified as nonlame, moderately lame, and lame, respectively. Most cows classified as lame had laminitis (54%) or disorders of the claw (33%). Median time to conception was 36 to 50 ...
Journal of Dairy Science, 2005
Trends in reproductive performance from 1976 to 2002 were studied for dairy farms located in Flor... more Trends in reproductive performance from 1976 to 2002 were studied for dairy farms located in Florida and Georgia using 2,897,517 Dairy Herd Improvement Association lactation records of Holstein cows. One-half of the 1552 herds in the final edited records had measures for at least 8 yr. Measures of reproductive performance changed significantly over time. Days to first service increased from a low of 84 d in 1983 to 104 d in 2001. Cows that calved during spring had 9.2 (1983) to 33.2 (1999) more days to first service than cows that calved during fall. Annual pregnancy rates (PR) for 71 to 364 d since last calving (DSC; PR 71-364) decreased from 21.6% in 1977 to 1979, to 12% in 2000 to 2002. The greatest PR 71-364 was observed during winter and the lowest during summer (15.8 vs. 5.6% in 2002, respectively). The absolute difference between PR 71-364 during winter and summer remained similar over time at 11 percentage units. Pregnancy rates in the early stages since calving (71 to 133 d) showed greater decreases over time than PR in the later stages since calving. From 1998 to 2002, PR in the later stages since calving (134 to 364 d) was on average 11.5%. Pregnancy rate from 71 to 133 DSC remained greater (13.4%). In the winter, the decrease in PR 71-364 was primarily due to a large decrease in PR 71-91. Average days to conception
Journal of Dairy Science, 2004
A longitudinal study was conducted to examine the relationship between lameness and delayed ovari... more A longitudinal study was conducted to examine the relationship between lameness and delayed ovarian cyclicity during the first 60 d postpartum and days to first luteal activity during the first 300 d postpartum in Holstein cows. Two hundred thirty-eight cows from a 600-cow dairy that calved during a 12-mo period were used. Cows were classified into 1 of 6 categories of lameness during the first 35 d postpartum using a locomotion scoring system. Cows were blood-sampled weekly for detection of plasma progesterone concentrations during the first 300 d postpartum. Cows with delayed resumption of ovarian cyclicity were defined as those with progesterone concentrations consistently <1 ng/mL during the first 60 d postpartum. The null hypothesis that risk of delayed cyclicity is the same in cows classified as nonlame, moderately lame, or lame (after adjusting for potential modifying or confounding effects of loss of body condition and other variables related with delayed cyclicity) was tested using logistic regression. Analysis of results of the study reported here support the hypothesis that lameness is associated with delayed ovarian activity in Holstein cows during the early postpartum period. Cows classified as lame had 3.5 times greater odds of delayed cyclicity, compared with cows classified as nonlame. Attributable proportion analysis indicated that delayed ovarian cyclicity in lame cows would be reduced by 71%, if lameness had been prevented.
Revista De La Facultad De Medicina Veterinaria Y De Zootecnia, May 3, 2010
From an animal health-well being, welfare, and performance perspective, the postpartum period is ... more From an animal health-well being, welfare, and performance perspective, the postpartum period is comprised of an early window where acute health and cow survival is an issue with the development of septic metritis. subsequently, sustained presence of endometritis is likely to be contributing to sub-fertility in lactating dairy cows with an overall herd pregnancy rate of approximately 16%. The challenge is to integrate on commercial dairies preventive medicine programs with reproductive management to improve herd fertility. Cows affected by periparturient disorders such as hypocalcemia, dystocia, and retained fetal membranes are more likely to contract uterine infections than cows that calve normally are. Thus, appropriate management of the transition period is critical in the prevention of uterine infections at the herd level. in addition, a postpartum program to monitor health to provide treatment to cows in the early stages of disease should be implemented.
Revista De La Facultad De Medicina Veterinaria Y De Zootecnia, May 3, 2010
Los días abiertos en el hato lechero dependen de muchos factores, dentro de los cuales se debe co... more Los días abiertos en el hato lechero dependen de muchos factores, dentro de los cuales se debe considerar, la preparación de la vaca preparto incluyendo el manejo dietario pre y postparto. Factores como la hipocalcemia y la condición corporal son determinantes en la presentación de patologías puerperales y en el inicio de la ciclicidad. adicional a este manejo, se debe considerar la utilización de protocolos de inseminación a tiempo fijo que incrementa el número de animales servidos cerca del tiempo voluntario de espera y genera un incremento en las tasas de preñez. La presente revisión discutirá temas relacionados con la condición corporal y la presentación de hipocalcemia puerperal que afectan la fertilidad posparto de la vaca, así como alternativas para mejorar las tasa de preñez y reducir los días abiertos.
The Canadian veterinary journal. La revue vétérinaire canadienne, 2007
Twenty-two cases of indigestion occurred in a 650-cow herd. Five cows had severe sand abomasal im... more Twenty-two cases of indigestion occurred in a 650-cow herd. Five cows had severe sand abomasal impaction, diagnosed by laparotomy. The pH of prepartum cows' urine was < 6.0 and of sand 8.0. Feed showed a dietary cation-anion difference < or = -110 mEq/kg. After feeding management corrections, no more cases were diagnosed.
Journal of Dairy Science, 2002
The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterifie... more The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and glucose in transition cows fed anionic salts prepartum and provided with calcium and energy supplements at calving. The study was conducted on a Florida Holstein dairy farm from November to December 1997. Treatments consisted of no treatment (n = 30); 60 g of Ca as calcium chloride, orally (n = 30); 110 g of Ca as calcium propionate 510 g plus 400 g of propylene glycol, orally (n = 30); two doses of 60 g of Ca as calcium chloride, one at calving and the second 24 h later, orally (n = 30); and 10 g of Ca as borogluconate, intravenously (n = 30). Treatments were administered within 12 h after parturition. Blood samples were collected at d 1 (parturition), 2, 3, 6, 9, and 12 after calving. Plasma total Ca, P, Mg, NEFA, BHBA, and glucose were measured. There were no differences in the concentrations of the blood metabolites among treatments.
Theriogenology, 2003
The objective of this study was to determine the effect of a calcium-energy supplement at calving... more The objective of this study was to determine the effect of a calcium-energy supplement at calving on the incidence of calving-related disorders (CRD), fertility, BCS and milk yield in cows fed anionic diets and to establish any associations among outcome variables. In Florida, from October to December 1997, 479 cows were assigned to three groups and treated at calving as follows: Group 1: 160 nontreated cows; Group 2: 158 cows, treated orally with 60 g Ca as CaCl 2 ; Group 3: 161 cows, treated orally with 110 g Ca as calcium propionate (510 g) plus propylene glycol (400 g). No treatment effect was detected for any of the outcome variables. An association was found between dystocia and age and retained fetal membranes (RFM). Age and RFM were associated with metritis. RFM and displacement of the abomasum were associated with ketosis. Ketosis and age were related to displacement of the abomasum. Parity, BCS, ovarian cysts, RFM and metritis were associated with fertility.
Theriogenology, 2006
The objective of this study was to evaluate the association between the level of milk production ... more The objective of this study was to evaluate the association between the level of milk production on the day of diagnosis of ovarian cysts and treatment response using the Ovsynch protocol. On the day of cyst diagnosis (Day 0), 260 lactating dairy cows with ovarian cysts were treated with gonadotropin-releasing hormone (GnRH), PGF2a on Day 7, GnRH on Day 9, and timed inseminated 16-20 h later (Ovsynch protocol). Pregnancy was determined (by transrectal palpation) between 42 and 49 days after insemination. On Day 0, data for milk production (kg/day), parity, days in milk (DIM), and body condition score (BCS) were recorded. Using the median value for milk production on the day of diagnosis, cows were classified as high producers (>28.5 kg) and low producers (28.5 kg). Cows were classified as primiparous (first lactation) or multiparous (second or more lactations). Data for conception rate (CR) were analyzed using logistic regression accounting for milk production on the day of diagnosis, parity, DIM, and BCS. The CR for low and high producers was 6 and 16%, respectively. There was no association between DIM and BCS with the other variables (P ! 0.05). Primiparous cows were more likely (adjusted odds ratio: AOR = 3.63; 95% CI: 95% confidence intervals = 1.28-10.30; P 0.01) to become pregnant than multiparous cows, and low producers were less likely (AOR = 0.31; 95% CI = 0.11-0.85; P 0.02) to become pregnant than high producers. It was concluded that cows with high milk production on the day of cyst diagnosis were more likely to become pregnant following treatment than cows with low milk production. It appears paradoxical that high milk production predisposes to the occurrence of ovarian cysts, but that high-producing cows respond better to treatment compared to low-producing cows. It is hypothesized that the level of milk production on the day of cyst diagnosis could be an additional potential predictor of success to treatment of lactating cows with ovarian cysts using the Ovsynch protocol.
Risco/Dairy Production Medicine, 2011
ABSTRACT
Hopper/Bovine Reproduction, 2014
Dairy Production Medicine, 2011
Risco/Dairy Production Medicine, 2011
... with various periparturient disorders such as uterine prolapse (Risco et al., 1984 ), retaine... more ... with various periparturient disorders such as uterine prolapse (Risco et al., 1984 ), retained fetal membranes (Risco et al., 1994 ; Mel é ndez et ... Cows with an abnormally enlarged uterus and a puru-lent uterine discharge without systemic signs of illness are classified as grade 1 ...
Veterinary Clinics of North America: Food Animal Practice, 2005
Veterinary Clinics of North America: Food Animal Practice, 2005
Vaccine, 2009
Mycoplasma bovis is an important cause of pneumonia, otitis media and arthritis in young dairy ca... more Mycoplasma bovis is an important cause of pneumonia, otitis media and arthritis in young dairy calves, and there is a critical need for improved preventative strategies for this pathogen. We conducted a randomized, placebo-controlled, double-blinded field trial to determine the efficacy of a commercial M. bovis vaccine for the prevention of M. bovis-associated disease in calves. Calves (n = 373) on 3 Florida dairies with a history of M. bovis infection received an M. bovis bacterin or a placebo, administered subcutaneously at 3, 14 and 35 days of age. One of the herds did not experience M. bovis-associated disease; for calves in the remaining 2 herds, the incidence risk for respiratory disease, otitis media and arthritis from 3 to 90 days of age was 0.64, 0.28 and 0.02, respectively. Vaccination had no effect on the age at first treatment for M. bovis-associated disease, incidence of respiratory disease, mortality, weight gain, or nasal colonization with M. bovis in the first 90 days of life. In one herd, vaccination was associated with an increased risk of otitis media. There was no association between M. bovis-specific serum antibody titers and morbidity in vaccinated calves. Under the field conditions in this study, this vaccine was not efficacious for the prevention of M. bovis-associated disease in young dairy calves.
Theriogenology, 2006
The objective of this study was to determine the effect of a monensin controlled-release capsule ... more The objective of this study was to determine the effect of a monensin controlled-release capsule on the incidence of retained fetal membranes (RFM), milk yield and conception rate at first service (CRFS). The study was conducted during May to August 2004 in a large dairy herd in Chihuahua, Mexico. Cows (n = 2025) from 20 to 30 d before expected parturition were randomly assigned to either a treatment or a control group. The treated group (n = 1010) received orally a capsule of monensin that released 335 mg/d for 95 d. Control cows (no capsule, n = 1015) were randomly assigned and matched by parity. Outcome variables were the incidence of RFM, first three test day milk and CRFS. Monensin decreased the incidence of RFM by 3.9% only in multiparous cows. Therefore, multiparous cows treated with monensin were 0.78 times (95% C.I. = 0.71-0.86) as likely as control multiparous cows to develop RFM. Overall, milk yield was negatively affected by the RFM condition, but it was improved by monensin only in multiparous cows with RFM at test day 1. Conception rate at first service was depressed by 10.6% in multiparous cows with RFM. However, in RFM cows treated with monensin, CRFS improved to the level of treated cows without RFM.
Research in Veterinary Science, 2007
The objective of this study was to determine the effect of a monensin controlled-release capsule ... more The objective of this study was to determine the effect of a monensin controlled-release capsule administered intraruminally at drying-off on body condition score (BCS) at calving, milk yield, fertility and concentration of energy-related blood metabolites in Holstein cows dried-off with low BCS (< or = 3.0, scale 1 to 5 with a 0.25 point of increment). Between July and August, 2001, 220 cows from parity 2 or more and dried-off 50-70 days before expected parturition, with a BCS < or = 3.0 were randomly assigned to either a treatment group (n=110; oral capsule of monensin releasing 335 mg/day for 95 days) or a control group (no capsule, n=110). At assignment, on day 21 before expected parturition, at calving, and at 7, 14, and 21 days in milk a blood sample was obtained from a random sub sample of 10 cows per group. Effects of monensin on serum NEFA, BHBA and glucose were measured. Milk yield, milk fat and protein content (%) at DHIA test days during the entire lactation, 305 ME milk production and reproductive responses were compared. Monensin significantly improved BCS at calving, increased milk yield at test days 4 and 8, decreased the percentage of milk protein, did not change the percentage of milk fat, and decreased NEFA and BHBA during the post-partum period.
Journal of the American Veterinary Medical Association, 2005
Objective—To compare calving-to-conception intervals among cows classified as nonlame, moderately... more Objective—To compare calving-to-conception intervals among cows classified as nonlame, moderately lame, or lame during the prebreeding postpartum period and to examine the relationship between severity of lameness and time to conception in cows that were classified as lame. Design—Longitudinal study. Animals—499 Holstein cows. Procedure—Cows in the prebreeding postpartum period were classified as nonlame, moderately lame, or lame by use of a 6-point locomotion scoring system. Time to conception (days) was compared among cows. A low, medium, or high cumulative locomotion score was assigned to lame cows, and time to conception among those cows was compared. Cows classified as lame were examined on a tilt table for diagnosis and treatment of lameness. Results—154 (31%), 214 (43%), and 131 (26%) cows were classified as nonlame, moderately lame, and lame, respectively. Most cows classified as lame had laminitis (54%) or disorders of the claw (33%). Median time to conception was 36 to 50 ...